Skin includes three layers: epidermis, dermis and subcutaneous tissue. Among these, dermis contains a high amount of collagen and elastin which are extracellular matrix components. The components are important for maintenance of skin functions such as skin elasticity and water retentivity. Collagen and elastin are produced by fibroblasts in dermis. When fibroblasts are however less functional due to stimulation by ultraviolet rays or aging, collagen and elastin in dermis are denatured or reduced the amount. As a result, skin undergoes senile change such as generation of wrinkles or sagging and reduction in skin function including water retentivity and elasticity.
Most parts of epidermis include keratinocytes. Keratinocytes grow in the basal layer, migrate into the horny layer and finally fall off as scurf. Thus the migration ability of keratinocytes is important for promotion of skin metabolism and maintenance of skin barrier function.
The ability of collagen and elastin production of fibroblasts and the migration ability of keratinocytes are also important for the wounds healing. For example, when dermis is lost due to a sever wound, granulation tissue must be generated to fill the region of the wound. The granulation tissue includes extracellular matrix such as fibroblasts and collagen produced by fibroblasts. Further, epidermis lost due to the wound is repaired by keratinocytes which migrate from the epidermal basal layer surrounding the region of the wound to cover the region of the wound.
For the purpose of prevention of senile change of skin or improvement of skin, various compositions have been developed so far including compositions containing saccharides, amino acids, organic acids and pyrrolidone carboxylic acid and compositions containing extracellular matrix components such as collagen.
Recently, attention is focused on lignans in sesame seeds which may be useful for amelioration of skin problems or suppression of skin inflammation. For example, Patent Literature 1 discloses use of sesame essential oil containing lignans as antioxidants for a composition for external use. Patent Literature 2 discloses a composition for external use containing a sesame lignan, sesamol.